Thrust washer structure



April 7, 1942. 'r. J. ZELLER ETAL THRUST WASHER STRUCTURE Filed Aug. '7', 1940 m im m mZL E IMF. N

ED 0 m m n m VA Patented Apr. 7, 1942 UNITED STATES PATENT OFFICE 2,278,578 rnausr WASHER s'TRuoTuRE Theodore J. Zelle'r Plainfield, and Sigmund F. Lisbon, North Plainfield, N. .L; as'signors to Mack Manufacturing CorporatiomLong Island City, N. Y., a corporation of Delaware Application Augu st 7, 1940, serial No 35-11660" 2 claims.- (01. 192-1095 This invention relates to clutches of the type including cooperating throwout" bearings and throwoutleversfor disengaging the friction ele-' mentsof the clutchesand relates more particu-{ larly to an improved thrust washer adapted to' be interposed'between the clutch throwout bearing and the clutch throwout levers to minimize wear thereof.

Clutches of the type ge nerally described above" usually include a plurality" of cooperating fric'- tion' elements which are normally urged together by means of springs and/or centrifugal force and are provided with a plurality of radially extending levers appropriately supported so that upon movement thereof in one direction, the friction surfaces are disengaged. Movement is imparted to the levers by means of a suitable throwoutbearing usually of the anti-friction or lubricated type, one race or element of which engages the inner ends of the throwout levers,

In some forms of clutches, the inner ends of the levers are out of contact'withallother parts of the clutch while the clutch is" engaged" and engage the throwoutbearing only when the clutch being disengaged.

Inother types of clutches; the inner ends ofthe clutchthrowout levers may becontinually engaged by elements forming a part of the throwout bearings. With either type, considerable wear" on the inner ends' o f the throwout levers" and the cooperating portion of the throwoutbearing occurs during disengagement of the clutch which causes the clutches to get outof adjustment;

An object of the invention is to provide an- Other objects of the invention will be apparent-from the following description of a typicalfo'rm-of thrust washer embodying the present invention. U

Thrust washers embodying the present inventiohconsistof annular members or rings which fi lid'wifltal Qf ci u snt ally sip Jed, axially extending flanges between" which alie'rejce 5 3 l qw o th flut h l' l out lev r Th dia dis i on. s o name; by the flanges prevents? extended" niove ment of the washer in a radial direction and thereby causes the washer to be disposedjconcentrfica-lly' with the" a'xis of rotation of the washer. the washer isself-centering and main tains a close engagement with the" ends of the throwout levers. I x f lvlore particularly, the washer cons'ists of an annular member whicli'is adapted to be interposed between the inner ends of the clutch throwout levers and the adjacent race or memoithe clutch throwout bearing; so that the washer receives substantially all of the-wear to whiehthe'clutch fingers would be subjected be- 1 cause of relative rotation between the thrjowout bee rig and the throwout levers. 'Ifhe"annular poi en of the washer adjacent the' throwout beefin is preferably provided; with a[ relatively wide-flat face which tends to distribute thewear on the throwout bearing over a wide areaa'rid thus uniformly distributes the wear on the beari The washer is pro vided ithamemberfor deta'chably retaining it on the ends; of the clutch fihg er" and out of contact with both-the throw out bearing an'd the drive shaft of the clutch on" which the b earing is supported while the clutch elements are engaged,-= thereby eliminating" the need for antifrictionor lubricatedbearingelements 'betweenthe washerfarid the shaft.

Provision is made for the? lubricatien' of: the ends" of the clutch fingers through leakage of lubricant from the throwout bearing through passageways in the thrust washer. v V

For a better understanding of the present inventioh, reference may be had to the accompanying drawing in which:

Figure 1 is a view in cross-section of a typical form of clutch to which'the thrust washer embodying the present invention isapplied;

Figure" 2' is an enlarged View in cross-section of a typical form-of washer embodying the' invention; and g I Figure 3 is a' view in section taken on line 3 3 of Figure'l.

A'thrust washer of a type embodying the invention is'disclosed in Figure 1 as applied to the forin' of clutch disclosed inthe Bruno Lo e'flle'r application Serial No. 244,529,*filed" December 8, 1938',-now U. S. Patent No. 2,251',143',"issued July This form of clutch consists generally of a fiywheel and clutch casing ID to which is connected a clutch element H which cooperates with a clutch disc l2 supported for axial movement, only, on a driven shaft l3. The clutch disc I2 is normally forced into engagement with the clutch element H by means of a pressure ring 14 which is mounted for relative axial movement on the clutch casing cover l5 by means of a plurality of lugs 18 and the eye bolts lfia supported thereon.

Suitable powerful springs (not shown) urge the pressure ring l4, the clutch disc l2 and the clutch element H into engagement for transmitting power from the motor to the driven shaft l3.

The eye bolts [6a are provided with fulcrum elements II which are adjustable along the eye bolt by means of suitable nuts [8. The fulcrum elements I! engage the outer surfaces of the clutch throwout levers [9 which are rockably mounted upon hemispherical lugs on the exterior of the cover l5. Suitable hemispherical sockets 2! on the throwout levers l9 permit free rocking movement of the throwout levers IS.

The throwout levers I9 are normally urged in a direction to withdraw the pressure ring l4 by means of coil springs 22 which engage the upper surface of the levers l9 and are supported upon the clutch is to be disengaged by means of a suitable throwout bearing either of the lubricated or an antifriction type which is supported for movement axially on the driven shaft [3. In the form of clutch illustrated, the throwout bearing 24 preferably is of the lubricated type, including an inner race (not shown), an outer race 25 engageable with the inner ends of the throwout levers I9, and a reservoir 26 for supplying lubricant to the bearing.

The thrust Washer 21 embodying the present invention consists generally of an annular or ring portion 28 having opposite fiat surfaces 29 and 30 which are adapted to engage respectively the outer race 25 of the throwout bearing and the inner ends of the clutch throwout levers 19. The ring 28 distributes the wear caused by slippage of the washer and the outer race of the bearing during acceleration of the outer race 25 to the speed of rotation of the clutch uniformly over the contacting face of the outer race 25 and thus causes it to wear evenly and much more slowly than if the ends of the levers l9 engaged the race directly.

Around the periphery of the annular or ring member 28 are a plurality of circumferentially spaced, axially extending flanges 3| of generally arcuate shape which define radially extending slots 32 between their adjacent ends. The slots 32 are of sufiicient width to receive closely the inner ends of the throwout levers l9. Inasmuch as the throwout levers l9 are radially directed and fit closely within the slots 32, they tend to limit the movement of the washer 21 in all radial directions. The washer, however, is free to move slightly relatively to these fingers so that centrifugal force normally causes the ring to center itself coaxially with the driven shaft l3 during the rotation of the clutch.

The internal diameter of the washer 21 preferably is such that it is entirely out of engagement with the driven shaft I3 as best shown in Figure 3, and thus rattling of the washer 21 on the shaft I3 and frictional engagement of the washer with the shaft are entirely eliminated.

The washer 28 may be detachably connected to the inner ends of the throwout levers 19 in any suitable way, but it is preferred to use a simple and inexpensive construction such as the snap ring 33, best shown in Figures 2 and 3. The snap ring 33 is an annular spring member having a transverse slit therein which permits it to be compressed in order to insert it between the ends of the levers l9 and the radially inwardly projecting flanges 34 at the outer ends of the flanges 3!. The clearance between the snap ring 33 and the ends of the throwout levers I9 is such that no interference with the adjustment of the levers with respect to the pressure ring [4 occurs.

When the Washer 21 and the race 25 of the throwout bearing 24 are properly spaced and the slots 32 are of proper depth, the washer 21 cannot become detached from the levers even if the snap ring 33 should be broken or fall out of the washer 2'1. The only result would be a slight rattling of the washer as it rocks relatively to the levers and the throwout bearing.

Proper lubrication of the inner ends of the levers I9 is obtained by means of a plurality of openings or passageways 35 extending transverse- 1y through the ring 28 and communicating with the bottoms of the slots 32. Lubricant leaking from the throwout bearing 24 passes through openings 35 to the levers l9.

From th foregoing description of a typical form of washer embodying the invention, it will be apparent that a very simple and effective washer has been provided for minimizing the wear on the ends of the throwout fingers and bearing, both of which are expensive elements to replace and difficult to adjust upon replacement. Inasmuch as such thrust washers are of simple construction and may be readily detached from the throwout levers by merely removing the snap ring 33, it will be apparent that replacement of the washer is a comparatively simple matter and is far less expensiv than the replacement of either the throwout levers or the throwout bear- It will be understood that the washer is susceptible to some variation, such as for example the thickness, weight and general shape of the elements thereof, and accordingly the form of washer described above should be considered as illustrative and not as limiting the scope of the following claims.

I claim:

1. In a clutch having cooperating friction elements normally urged into engagement, shaft-s supporting said friction elements, a plurality of radially extending throwout levers, a throwout bearing mounted about one of said shafts and an annular thrust washer connecting the inner ends of said levers for actuation by said bearing; said thrust washer being characterized in that it is provided with a plurality of recesses into which the inner ends of said levers are pivotally received, said washer being adapted to be engaged on one side thereof by said throwout bearing, and said washer having passageways extending from said one side to said recesses for passage of lubricant from the throwout bearing to the engaging surfaces of the inner ends of said throwout levers.

2. In a clutch having cooperating friction elements normally urged into engagement, shafts allow said levers to center the member about said one shaft in position to be engaged only by said throwout bearing on the side thereof opposite from said flanges, and said member being. provided with passages from the side adapted to be engaged by said bearing to the inner sides of said slots for passage of lubricant from the bearing to the ends of said levers.

THEODORE J. ZELLER. SIGMUND F. LISBON. 

